The present invention relates to a rotational motion drive device between the needle cylinder and the dial in circular hosiery machines or the like. These are provided with a program chain advancing at each revolution and with a program drum advancing by intermittently with the action of the chain (or of members equivalent to the chain and drum). According to the invention, there is provided a clutch to couple and disengage two drive members between the cylinder and the dial, upon the control of the program chain to interrupt the dial rotational motion when and until the members thereof are not required, and to assure an engagement in one or more well defined relative angular positions.
The device may be provided in machines of the aforesaid kind, which are equipped to create closures of a tubular article according to, for example, U.S. Pat. Nos. 3,340,706 and 3,327,500, and Italian Pat. No. 736,075. To realize the above, shifts or phase displacements must be determined cyclically according to angles smaller than 360.degree. between cylinder and plate. Therefore, the machines in this case involve a double front clutch having a single clutching position and being phase-shifted in the two coupling conditions, with two opposite and shifted front tooth profiles, and with a unit slidable axially to alternatively attain -- upon the control of the drum -- the two engaging positions with the two opposite profiles.